检索结果-南通市图书馆

Peculiarities of Ethylene Polymerization Reactions with Bis(imino)pyridyl Complexes of CoCl_(2) and FeCl_(2)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第4期42卷 492-500页

作者： Laura A.Rishina Yury V.Kissin Svetlana S.Lalayan Artem A.Antonov Vadim G.Krasheninnikov alexander A.Gulin N.N.Semenov Federal Research Center for Chemical Physics Russian Academy of Sciences4 Kosygin St.Moscow119991Russia Department of Chemistry and Chemical Biology RutgersThe State University of New Jersey123 Bevier Rd.PiscatawayNJ08854USA Boreskov Institute of Catalysis Russian Academy of Sciences5 Lavrentieva Prosp.Novosibirsk630090Russia

The article describes ethylene polymerization reactions with transition metal catalysts based on complexes of CoCl_(2) and FeCl_(2) with an N,N,N-tridentate ligand 2,6-bis[1-(2,6-dimethylphenylimino)ethyl]pyridine. The complexes are converted into polymerization catalysts by reacting them either with polymethylalumoxane (MAO) or with a combination of Al(C2H5)2Cl and Mg(C4H9)2 at an [Al]:[Mg] ratio of ~3. Both MAO-activated complexes readily polymerize ethylene at 35 ℃ with the formation of linear, low molecular weight polymers with a narrow molecular weight distribution. The same complexes, when activated with the Al(C2H5)2Cl-Mg(C4H9)2 combination, form multi-center catalysts and generate polyethylenes with a broad molecular weight distribution.

关键词： Ethylene polymerization Bis(imino)pyridyl complexes of CoCl_(2)and FeCl_(2) Molecular-weight distribution Polymer chain structure

维普期刊数据库

Understanding the ef fect of recreational drug use on bone health and musculoskeletal disease in the establishment of pain regimens

在线全文

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2024年

作者： Ariella Gartenberg alexander Petrie Winston Yen Woojn Cho Emergency Medicine Department Montetore Medical Center and Jacobi Medical Center Emergency Medicine Department Jacobi Medical Center and North Central Bronx Touro College of Osteopathic Medicine Touro University

BACKGROUND:The widespread use of recreational drugs has raised concerns regarding their effects on various organ *** use of cannabis and opioids in chronic pain management increases their prevalence among patients with musculoskeletal conditions whose bone health may already be *** article aims to review the pathophysiology and toxic effects of recreational drug use on musculoskeletal health to establish appropriate pain regimens for patients with substance ***:Medical literature published from 1970 until 2022 was identified utilizing MEDLINE/PubMed and the Cochrane *** addition to the databases,references were obtained through the use of reference lists of published articles identified by the aforementioned *** initial search terms included opioids,inhalants,hallucinogens,cannabis,stimulants,and bone *** were no methodological limitations in relation to the initial acquisition and analysis of ***:A total of 55 research articles were included in this ***,stimulants,opioids,and inhalants impact bone maintenance,specifically osteoblast and osteoclast activity,as well as impede hormone *** substances inhibit bone remodeling and development,manifesting as lower bone mineral density and increased fracture risk in chronic ***:Although the current literature suggests a deleterious effect of recreational drugs on bone health and musculoskeletal disease,further research is warranted to evaluate the clinical effects of long-term substance *** evaluation of such effects will aid in establishing appropriate pain regimens,as well as appropriate screening and treatment plans for recreational drug users.

关键词：

Post-operative morbidity after neoadjuvant chemotherapy and resection for gallbladder cancer: A national surgical quality improvement program analysis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Surgery 2024年第1期16卷 95-102页

作者： Minha Kim Stephanie Stroever Krist Aploks alexander Ostapenko Xiang Da Dong Ramanathan Seshadri Department of General Surgery Danbury HospitalDanburyCT 06810United States Department of Research and Innovation Nuvance HealthDanburyCT 06810United States Division of Surgical Oncology/Hepato-Pancreato-Biliary Surgery Danbury HospitalDanburyCT 06810United States

BACKGROUND Gallbladder cancer is the most common malignancy of the biliary ***-adjuvant chemotherapy(NACT)has improved overall survival by enabling R0 ***,there is no consensus of guidelines for neoadjuvant therapy in gallbladder *** investigations continue to analyze the regimen and benefit of NACT for ongoing care of gallbladder cancer patients,we examined American College of Surgeons National Surgical Quality Improvement Program(NSQIP)database to determine if there was higher morbidity among the neo-adjuvant group within the 30-day post-operative *** hypothesized patients who underwent NACT were more likely to have higher post-operative *** To investigate the 30-day post-operative morbidity outcomes between patients who received NACT and underwent surgery and patients who only had *** A retrospective analysis of the targeted hepatectomy NSQIP data between 2015 and 2019 was performed to determine if NACT in gallbladder cancer increased the risk for post-operative morbidity(bile leak,infection rate,rate of converting to open surgery,etc.)compared to the group who only had *** calculate the odds ratio for the primary and secondary outcomes,a crude logistic regression was *** Of the 452 patients,52 patients received NACT prior to *** were no statistically significant differences in the odds of morbidity between the two groups,including bile leak[odds ratio(OR),0.69;95%confidence interval(95%CI):0.16-2.10;P=0.55],superficial wound infection(OR,0.58;95%CI:0.03-3.02;P=0.61),and organ space wound infection(OR,0.63;95%CI:0.18-1.63;P=0.61).CONCLUSION There was no significant difference in the risk of 30-day post-operative morbidity between the NACT and surgery group and the surgery only group.

关键词： Gallbladder cancer Neoadjuvant chemotherapy Radical cholecystectomy National Surgery Quality Improvement Program Postoperative outcome

A new look at the first dinosaur discovered in Antarctica: reappraisal of Antarctopelta oliveroi(Ankylosauria: Parankylosauria)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Polar Science 2024年

作者： Sergio SOTO ACU?A alexander O.VARGAS Jonatan KALUZA Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Red Paleontológica U-Chile Departamento de Biología Facultad de Ciencias Universidad de Chile Fundación de Historia Natural Félix de Azara Universidad Maimónides Escuela de Geología Facultad de Ciencias Ingeniería y Tecnología Universidad Mayor Providencia

The first dinosaur discovered in the Antarctic continent was the ankylosaur Antarctopelta oliveroi in the 1980s. Nevertheless， since then several hypotheses of phylogenetical relationships have been proposed because these have been depended on how the skeletal remains have been interpreted. The main obstacle for clarifying its phylogenetic position is that many portions of the skeleton remain unknown， in addition to the presence of unknown characters in typical ankylosaurs. Considered an ankylosaurid， nodosaurid， or even a chimaera， a recent proposal based on mostly complete material of a new ankylosaur from Chilean Patagonia provided support for a novel phylogenetic hypothesis: Antarctopelta and other southern ankylosaurs are an early branching clade， the Parankylosauria， whose origin probably dates to the Late Jurassic. In the light of this new view， a redescription of the available skeletal remains is provided together with a new reconstruction of the first Antarctic dinosaur known to the science community.

关键词：

Insights into the hydrogen evolution reaction in vanadium redox flow batteries:A synchrotron radiation based X-ray imaging study

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第4期91卷 132-144页

作者： Kerstin Köble Alexey Ershov Kangjun Duan Monja Schilling alexander Rampf Angelica Cecilia TomášFaragó Marcus Zuber Tilo Baumbach Roswitha Zeis Helmholtz Institute Ulm Karlsruhe Institute of Technology89081 UlmGermany Laboratory for Applications of Synchrotron Radiation Karlsruhe Institute of Technology76131 KarlsruheGermany Institute for Photon Science and Synchrotron Radiation Karlsruhe Institute of Technology76344 Eggenstein-LeopoldshafenGermany Department of Electrical Electronicsand Communication EngineeringFaculty of EngineeringFriedrich-Alexander-Universität Erlangen-Nürnberg(FAU)91058 ErlangenGermany Department of Mechanical and Industrial Engineering University of TorontoToronto M5S 3G8OntarioCanada

The parasitic hydrogen evolution reaction(HER)in the negative half-cell of vanadium redox flow batteries(VRFBs)causes severe efficiency ***,a deeper understanding of this process and the accompanying bubble formation is *** benchmarking study locally analyzes the bubble distribution in thick,porous electrodes for the first time using deep learning-based image segmentation of synchrotron X-ray *** large three-dimensional data set was processed precisely in less than one minute while minimizing human errors and pointing out areas of increased HER activity in *** study systematically varies the electrode potential and material,concluding that more negative electrode potentials of-200 m V *** hydrogen electrode(RHE)and lower cause more substantial bubble formation,resulting in bubble fractions of around 15%–20%in carbon felt ***,the bubble fractions stay only around 2%in an electrode combining carbon felt and carbon *** detected areas with high HER activity,such as the border subregion with more than 30%bubble fraction in carbon felt electrodes,the cutting edges,and preferential spots in the electrode bulk,are potential-independent and suggest that larger electrodes with a higher bulk-to-border ratio might reduce HER-related performance *** described combination of electrochemical measurements,local X-ray microtomography,AI-based segmentation,and 3D morphometric analysis is a powerful and novel approach for local bubble analysis in three-dimensional porous electrodes,providing an essential toolkit for a broad community working on bubble-generating electrochemical systems.

关键词： Vanadium redox flow battery Synchrotron X-ray imaging Tomography Hydrogen evolution reaction Gas bubbles Deep learning

维普期刊数据库

The Effect of a Monatomic Layer on a Surface on the Transition Radiation

在线全文

学校读者我要写书评

暂无评论

Journal of High Energy Physics, Gravitation and Cosmology 2024年第2期10卷 710-723页

作者： alexander N. Safronov Obukhov Institute of Atmospheric Physics Russian Academy of Sciences Moscow Russia

The transition radiation of a charged particle crossing the interface of two media having a monatomic impurity layer is investigated. It is shown that at sliding angles of incidence of a particle on the boundary of the media, the transition radiation is mainly determined by the properties of the surface layer. The possibility of using transition radiation to study the surface of substances is discussed. In addition, due to the hard radiation present in space, this research may be important for the use of light monoatomic layers as a material for satellite antennas, “solar sails” and cover layers in a future space (interstellar) mission.

关键词： Relativistic Charged Particle Transition Radiation Monatomic Layer Spectral Angular Distribution of Radiation Sliding Angle Investigation of Thin Films Interstellar Mission

Impact of exercise on markers of B cell-related immunity:A systematic review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Sport and Health Science 2024年第3期13卷 339-352,I0002页

作者： David Walzik Sergen Belen Karen Wilisch Marie Kupjetz Silvana Kirschke Tobias Esser Niklas Joisten alexander Schenk Sebastian Proschinger Philipp Zimmer Division of Performance and Health(Sports Medicine) Institute for Sport and Sport ScienceTU Dortmund UniversityDortmund 44227Germany

Background:B cells represent a crucial component of adaptive immunity that ensures long-term protection from infection by generating pathogen-specific *** alters B cell counts and immunoglobulin levels,but evidence-based conclusions on potential benefits for adaptive immunity are *** systematic review assessed current literatures on the impact of acute exercise and exercise training on B cells,immunoglobulins,and markers of secretory immunity in human ***:According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines,MEDLINE,Web of Science,and Embase were searched on March 8,***-randomized controlled trials and crossover trials investigating the impact of acute exercise or exercise training on B cell counts and proportions,immunoglobulin levels,salivary flow rate,or secretory immunoglobulin A secretion rate were *** and reporting of exercise training studies were assessed using the Tool for the Assessment of Study Quality and reporting in *** characteristics,outcome measures,and statistically significant changes were summarized ***:Of the 67 eligible studies,22 applied acute exercise and 45 applied exercise *** included outcomes revealed significant alterations over time in acute exercise and exercise training context,but only a few investigations showed significant differences compared to control *** and plasma immunoglobulin A levels were most consistently increased in response to exercise ***:B cell-related outcomes are altered by acute exercise and exercise training,but evidence-based conclusions cannot be drawn with high confidence due to the large heterogeneity in populations and exercise ***-designed trials with large sample sizes are needed to clarify how exercise shapes B cell-related immunity.

关键词： Antibody B-lymphocyte Exercise Humoral immunity Immune system

维普期刊数据库

在线全文

学校读者我要写书评

暂无评论

What Slowdown?

ChinAfrica 2024年第7期16卷 44-45页

作者： alexander AYERTEY ODONKOR 不详

China remains a key source of growth and profits for many multinationals In March,Apple opened its largest retail store on the Chinese mainland in Shanghai-the company’s second-largest flagship store after its Fifth Avenue outlet in New *** new addition brings Apple’s store tally in Shanghai and the Chinese market to eight and 57,respectively,a significant milestone for the company,which opened its first store in China in 2008.

关键词： store retail Avenue

Life Origin in the Milky Way Galaxy: III. Spatial Distribution of Overheated Stars in the Solar Neighborhood

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of High Energy Physics, Gravitation and Cosmology 2024年第2期10卷 693-709页

作者： alexander N. Safronov Obukhov Institute of Atmospheric Physics Russian Academy of Sciences Moscow Russia

A concept of ensemble averaged stellar reactors is developed to study the dynamics of processes occurring in stars, allocated in the ~200 pc solar neighborhood. According to the effective temperature value, four stellar classes are identified, for which the correlation coefficients and standard deviation are counted. The theory of the buoyancy terrestial elements is generalized to stellar systems. It was suggested that stars are over-heated due to the shift parameters of the nuclear processes occurring inside the stars, which leads to the synthesis of transuranium elements until the achievement of a critical nuclear mass and star explosion. The heavy transuranium elements sink downward and are concentrated in the stellar depth layers. The physical explanation of the existence of the critical Chandrasekhar star limit has been offered. Based on the spatial analysis of overheated stars, it was suggested that the withdrawal of the stellar reactor from the equilibrium state is a consequence of extragalactic compression inside the galaxy arm due to the arm spirality (not to be confused with the spirality of the galaxy itself).

关键词： Stellar Nucleogenesis Ensemble-Averaged Stellar Reactor Overheated Stars Chandrasekhar Stellar Limit Arm Spirality